Brhadaranyaka Upanishad - This book presents a lucid exposition of select portions of this Upanishad in the light of modern thought and modern needs. The Revered Swami has done this by freely drawing from contemporary scientific thought, biology, and physics, and by laying stress on the relevance of Vedantic ideas to these areas of modern thought.
The important thing is how much less you think of the body, of yourself as matter -- as dead, dull, insentient matter; how much more you think of yourself as shining immortal being. The more you think of yourself as spirit, the more eager you will be to be absolutely free from matter, body and senses. This is the intense desire to be free.
-Swami Vivekananda